190-00906-01
GTX 23 Installation Manual
Rev. C
Page 2-3
2.3 Installation Considerations
2.3.1 Preservation of Previous Systems
It is the installer’s responsibility to preserve the essential characteristic of the aircraft being modified with
this equipment to be in accordance with the aircraft manufacturer’s original design. This includes the
preservation of multiple power buses, which reduces the probability of interrupting power to essential
instruments and avionics.
2.3.2 Antenna Location Considerations
The antenna should be installed in accordance with AC 43.12-2A Chapter 3.
Figure 2-1. Antenna Installation Considerations
a. The antenna (Garmin P/N 010-10160-00 or equivalent) should be mounted away from major pro-
trusions, such as engine(s), propeller(s), and antenna masts. It should also be as far as practical
from landing gear doors, access doors, or other openings that could shadow (block) the signal
between the transponder antenna and ATC radar on TCAS.
b. The antenna should be mounted vertically on the bottom of the aircraft (Figure 2-1).
c. Antenna Separation: DME and TCAS receive signals in the same frequency range that aviation
transponders transmit at, so their antennas should be separated from the transponder antenna by as
much as feasible. Six feet of separation is a guideline. Radar altimeters (should one be installed
on an aircraft with a GTX 23) also have some potential to receive interference from a transponder
(the transponders’ fourth harmaonic), so it is good practice to separate transponder and radar
altimeter antennas by as much as practical also. Avoid mounting the antenna within three feet of
the ADF sense antenna or any other communication antenna.
d. To prevent RF interference, the antenna must be physically mounted a minimum distance of three
feet from the GTX 23.
NOTE
If the antenna is being installed on a composite aircraft, sufficient ground plane material
must be added. Conductive wire mesh, radials, or thin aluminum sheets embedded in the
composite material provide the proper ground plane allowing the antenna gain pattern to
be maximized for optimum transponder performance.
Mount Antenna on
Bottom of Aircraft
